diff --git a/doc/buffered_channel.qbk b/doc/buffered_channel.qbk
index 3aa00c6f..0323cbfb 100644
--- a/doc/buffered_channel.qbk
+++ b/doc/buffered_channel.qbk
@@ -8,7 +8,7 @@
 [section:buffered_channel Buffered Channel]
 
 __boost_fiber__ provides a bounded, buffered channel (MPMC queue) suitable to
-synchonize fibers (running on same or different threads) via asynchronouss
+synchronize fibers (running on the same or different threads) via asynchronous
 message passing.
 
     typedef boost::fibers::buffered_channel< int > channel_t;
diff --git a/include/boost/fiber/buffered_channel.hpp b/include/boost/fiber/buffered_channel.hpp
index 7ff7d5b7..492486d3 100644
--- a/include/boost/fiber/buffered_channel.hpp
+++ b/include/boost/fiber/buffered_channel.hpp
@@ -80,12 +80,22 @@ class buffered_channel {
     buffered_channel & operator=( buffered_channel const&) = delete;
 
     bool is_closed() const noexcept {
-        detail::spinlock_lock lk{ splk_ };
+        detail::spinlock_lock lk{splk_, std::defer_lock};
+        for(;;) {            
+            if(lk.try_lock())
+                break;
+            context::active()->yield();            
+        }
         return is_closed_();
     }
 
     void close() noexcept {
-        detail::spinlock_lock lk{ splk_ };
+        detail::spinlock_lock lk{splk_, std::defer_lock};
+        for(;;) {            
+            if(lk.try_lock())
+                break;
+            context::active()->yield();            
+        }
         if ( ! closed_) {
             closed_ = true;
             waiting_producers_.notify_all();
@@ -94,7 +104,12 @@ class buffered_channel {
     }
 
     channel_op_status try_push( value_type const& value) {
-        detail::spinlock_lock lk{ splk_ };
+        detail::spinlock_lock lk{splk_, std::defer_lock};
+        for(;;) {            
+            if(lk.try_lock())
+                break;
+            context::active()->yield();            
+        }
         if ( BOOST_UNLIKELY( is_closed_() ) ) {
             return channel_op_status::closed;
         }
@@ -107,8 +122,14 @@ class buffered_channel {
         return channel_op_status::success;
     }
 
-    channel_op_status try_push( value_type && value) {
-        detail::spinlock_lock lk{ splk_ };
+    channel_op_status try_push( value_type && value) {        
+               
+        detail::spinlock_lock lk{splk_, std::defer_lock};
+        for(;;) {            
+            if(lk.try_lock())
+                break;
+            context::active()->yield();            
+        }
         if ( BOOST_UNLIKELY( is_closed_() ) ) {
             return channel_op_status::closed;
         }
@@ -124,7 +145,11 @@ class buffered_channel {
     channel_op_status push( value_type const& value) {
         context * active_ctx = context::active();
         for (;;) {
-            detail::spinlock_lock lk{ splk_ };
+            detail::spinlock_lock lk{splk_, std::try_to_lock};
+            if (!lk) {
+                active_ctx->yield();
+                continue;
+            }
             if ( BOOST_UNLIKELY( is_closed_() ) ) {
                 return channel_op_status::closed;
             }
@@ -142,7 +167,11 @@ class buffered_channel {
     channel_op_status push( value_type && value) {
         context * active_ctx = context::active();
         for (;;) {
-            detail::spinlock_lock lk{ splk_ };
+            detail::spinlock_lock lk{splk_, std::try_to_lock};
+            if (!lk) {
+                active_ctx->yield();
+                continue;
+            }
             if ( BOOST_UNLIKELY( is_closed_() ) ) {
                 return channel_op_status::closed;
             }
@@ -178,7 +207,11 @@ class buffered_channel {
         context * active_ctx = context::active();
         std::chrono::steady_clock::time_point timeout_time = detail::convert( timeout_time_);
         for (;;) {
-            detail::spinlock_lock lk{ splk_ };
+            detail::spinlock_lock lk{splk_, std::try_to_lock};
+            if (!lk) {
+                active_ctx->yield();
+                continue;
+            }
             if ( BOOST_UNLIKELY( is_closed_() ) ) {
                 return channel_op_status::closed;
             }
@@ -201,7 +234,11 @@ class buffered_channel {
         context * active_ctx = context::active();
         std::chrono::steady_clock::time_point timeout_time = detail::convert( timeout_time_);
         for (;;) {
-            detail::spinlock_lock lk{ splk_ };
+            detail::spinlock_lock lk{splk_, std::try_to_lock};
+            if (!lk) {
+                active_ctx->yield();
+                continue;
+            }
             if ( BOOST_UNLIKELY( is_closed_() ) ) {
                 return channel_op_status::closed;
             }
@@ -220,7 +257,12 @@ class buffered_channel {
     }
 
     channel_op_status try_pop( value_type & value) {
-        detail::spinlock_lock lk{ splk_ };
+        detail::spinlock_lock lk{splk_, std::defer_lock};
+        for(;;) {            
+            if(lk.try_lock())
+                break;
+            context::active()->yield();            
+        }
         if ( is_empty_() ) {
             return is_closed_()
                 ? channel_op_status::closed
@@ -235,7 +277,11 @@ class buffered_channel {
     channel_op_status pop( value_type & value) {
         context * active_ctx = context::active();
         for (;;) {
-            detail::spinlock_lock lk{ splk_ };
+            detail::spinlock_lock lk{splk_, std::try_to_lock};
+            if (!lk) {
+                active_ctx->yield();
+                continue;
+            }
             if ( is_empty_() ) {
                 if ( BOOST_UNLIKELY( is_closed_() ) ) {
                     return channel_op_status::closed;
@@ -253,7 +299,11 @@ class buffered_channel {
     value_type value_pop() {
         context * active_ctx = context::active();
         for (;;) {
-            detail::spinlock_lock lk{ splk_ };
+            detail::spinlock_lock lk{splk_, std::try_to_lock};
+            if (!lk) {
+                active_ctx->yield();
+                continue;
+            }
             if ( is_empty_() ) {
                 if ( BOOST_UNLIKELY( is_closed_() ) ) {
                     throw fiber_error{
@@ -283,7 +333,11 @@ class buffered_channel {
         context * active_ctx = context::active();
         std::chrono::steady_clock::time_point timeout_time = detail::convert( timeout_time_);
         for (;;) {
-            detail::spinlock_lock lk{ splk_ };
+            detail::spinlock_lock lk{splk_, std::try_to_lock};
+            if (!lk) {
+                active_ctx->yield();
+                continue;
+            }
             if ( is_empty_() ) {
                 if ( BOOST_UNLIKELY( is_closed_() ) ) {
                     return channel_op_status::closed;
diff --git a/include/boost/fiber/detail/cpu_relax.hpp b/include/boost/fiber/detail/cpu_relax.hpp
index 54cecf12..f79d0ed7 100644
--- a/include/boost/fiber/detail/cpu_relax.hpp
+++ b/include/boost/fiber/detail/cpu_relax.hpp
@@ -59,7 +59,11 @@ namespace detail {
 //               processors
 // extended mnemonics (available with POWER7)
 // yield   ==   or 27, 27, 27
+# if defined(__POWERPC__) // Darwin PPC
+# define cpu_relax() asm volatile ("or r27,r27,r27" ::: "memory");
+# else
 # define cpu_relax() asm volatile ("or 27,27,27" ::: "memory");
+# endif
 #elif BOOST_ARCH_X86
 # if BOOST_COMP_MSVC || BOOST_COMP_MSVC_EMULATED
 #  define cpu_relax() YieldProcessor();
diff --git a/src/waker.cpp b/src/waker.cpp
index 0abffd10..1444dea4 100644
--- a/src/waker.cpp
+++ b/src/waker.cpp
@@ -31,7 +31,11 @@ wait_queue::suspend_and_wait_until( detail::spinlock_lock & lk,
     // suspend this fiber
     if ( ! active_ctx->wait_until( timeout_time, lk, waker(w)) ) {
         // relock local lk
-        lk.lock();
+        for(;;) {            
+            if(lk.try_lock())
+                break;
+            active_ctx->yield();            
+        }
         // remove from waiting-queue
         if ( w.is_linked()) {
             slist_.remove( w);